Manuscript Summary: The Directorium perpetuum of the monastery of St. Gall, commissioned by Abbot Franz von Gaisberg (1504–1529), consists of seven volumes (Cod. Sang. 533–539). A total of 36 regulaecontain the liturgical rules for the Liturgy of the Hours for all possible annual calendars, due to the variable date of Easter. Each rule begins with Epiphany; the rules for the holidays of the Christmas season until the Vigil of Epiphany (which do not depend on the date of Easter) are compiled in Cod. Sang. 539. Cod. Sang. 534 contains the third through tenth rules, for when Easter falls between the 24th and the 31st of March (reference date in the codex: Septuagesima, January 20th to 27th). The illumination of the manuscript is by Nikolaus Bertschi from Rorschach and an assistant: p. 3, 41, 83, 135, 243, 301 and 360 contain initials in opaque colors (partly on a background of gold leaf) with scrolls or richly decorated borders. This volume was written by the St. Gall cathedral organist Fridolin Sicher. As only one of the seven volumes, this one used to be a liber catenatus. (sno)